| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `lib/ungrammar/src/lib.rs`."><title>lib.rs - source</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Italic-81dc35de.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-MediumItalic-ccf7e434.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2"href="../../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../../static.files/rustdoc-e56847b5.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="ungrammar" data-themes="" data-resource-suffix="" data-rustdoc-version="1.91.0 (f8297e351 2025-10-28)" data-channel="1.91.0" data-search-js="search-e256b49e.js" data-stringdex-js="stringdex-c3e638e9.js" data-settings-js="settings-c38705f0.js" ><script src="../../static.files/storage-e2aeef58.js"></script><script defer src="../../static.files/src-script-813739b1.js"></script><script defer src="../../src-files.js"></script><script defer src="../../static.files/main-6dc2a7f3.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-263c88ec.css"></noscript><link rel="alternate icon" type="image/png" href="../../static.files/favicon-32x32-eab170b8.png"><link rel="icon" type="image/svg+xml" href="../../static.files/favicon-044be391.svg"></head><body class="rustdoc src"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="src-sidebar-title"><h2>Files</h2></div></nav><div class="sidebar-resizer" title="Drag to resize sidebar"></div><main><section id="main-content" class="content"><div class="main-heading"><h1><div class="sub-heading">ungrammar/</div>lib.rs</h1><rustdoc-toolbar></rustdoc-toolbar></div><div class="example-wrap digits-3"><pre class="rust"><code><a href=#1 id=1 data-nosnippet>1</a><span class="doccomment">//! Ungrammar -- a DSL for specifying concrete syntax tree grammar. |
| <a href=#2 id=2 data-nosnippet>2</a>//! |
| <a href=#3 id=3 data-nosnippet>3</a>//! Producing a parser is an explicit non-goal -- it's ok for this grammar to be |
| <a href=#4 id=4 data-nosnippet>4</a>//! ambiguous, non LL, non LR, etc. |
| <a href=#5 id=5 data-nosnippet>5</a>//! |
| <a href=#6 id=6 data-nosnippet>6</a>//! See this |
| <a href=#7 id=7 data-nosnippet>7</a>//! [introductory post](https://rust-analyzer.github.io/blog/2020/10/24/introducing-ungrammar.html) |
| <a href=#8 id=8 data-nosnippet>8</a>//! for details. |
| <a href=#9 id=9 data-nosnippet>9</a> |
| <a href=#10 id=10 data-nosnippet>10</a></span><span class="attr">#![deny(missing_debug_implementations)] |
| <a href=#11 id=11 data-nosnippet>11</a>#![deny(missing_docs)] |
| <a href=#12 id=12 data-nosnippet>12</a>#![deny(rust_2018_idioms)] |
| <a href=#13 id=13 data-nosnippet>13</a> |
| <a href=#14 id=14 data-nosnippet>14</a></span><span class="kw">mod </span>error; |
| <a href=#15 id=15 data-nosnippet>15</a><span class="kw">mod </span>lexer; |
| <a href=#16 id=16 data-nosnippet>16</a><span class="kw">mod </span>parser; |
| <a href=#17 id=17 data-nosnippet>17</a> |
| <a href=#18 id=18 data-nosnippet>18</a><span class="kw">use </span>std::{ops, str::FromStr}; |
| <a href=#19 id=19 data-nosnippet>19</a> |
| <a href=#20 id=20 data-nosnippet>20</a><span class="kw">pub use </span>error::{Error, <span class="prelude-ty">Result</span>}; |
| <a href=#21 id=21 data-nosnippet>21</a> |
| <a href=#22 id=22 data-nosnippet>22</a><span class="doccomment">/// Returns a Rust grammar. |
| <a href=#23 id=23 data-nosnippet>23</a></span><span class="kw">pub fn </span>rust_grammar() -> Grammar { |
| <a href=#24 id=24 data-nosnippet>24</a> <span class="kw">let </span>src = <span class="macro">include_str!</span>(<span class="string">"../rust.ungram"</span>); |
| <a href=#25 id=25 data-nosnippet>25</a> src.parse().unwrap() |
| <a href=#26 id=26 data-nosnippet>26</a>} |
| <a href=#27 id=27 data-nosnippet>27</a> |
| <a href=#28 id=28 data-nosnippet>28</a><span class="doccomment">/// A node, like `A = 'b' | 'c'`. |
| <a href=#29 id=29 data-nosnippet>29</a>/// |
| <a href=#30 id=30 data-nosnippet>30</a>/// Indexing into a [`Grammar`] with a [`Node`] returns a reference to a |
| <a href=#31 id=31 data-nosnippet>31</a>/// [`NodeData`]. |
| <a href=#32 id=32 data-nosnippet>32</a></span><span class="attr">#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)] |
| <a href=#33 id=33 data-nosnippet>33</a></span><span class="kw">pub struct </span>Node(usize); |
| <a href=#34 id=34 data-nosnippet>34</a> |
| <a href=#35 id=35 data-nosnippet>35</a><span class="doccomment">/// A token, denoted with single quotes, like `'+'` or `'struct'`. |
| <a href=#36 id=36 data-nosnippet>36</a>/// |
| <a href=#37 id=37 data-nosnippet>37</a>/// Indexing into a [`Grammar`] with a [`Token`] returns a reference to a |
| <a href=#38 id=38 data-nosnippet>38</a>/// [`TokenData`]. |
| <a href=#39 id=39 data-nosnippet>39</a></span><span class="attr">#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)] |
| <a href=#40 id=40 data-nosnippet>40</a></span><span class="kw">pub struct </span>Token(usize); |
| <a href=#41 id=41 data-nosnippet>41</a> |
| <a href=#42 id=42 data-nosnippet>42</a><span class="doccomment">/// An Ungrammar grammar. |
| <a href=#43 id=43 data-nosnippet>43</a></span><span class="attr">#[derive(Default, Debug)] |
| <a href=#44 id=44 data-nosnippet>44</a></span><span class="kw">pub struct </span>Grammar { |
| <a href=#45 id=45 data-nosnippet>45</a> nodes: Vec<NodeData>, |
| <a href=#46 id=46 data-nosnippet>46</a> tokens: Vec<TokenData>, |
| <a href=#47 id=47 data-nosnippet>47</a>} |
| <a href=#48 id=48 data-nosnippet>48</a> |
| <a href=#49 id=49 data-nosnippet>49</a><span class="kw">impl </span>FromStr <span class="kw">for </span>Grammar { |
| <a href=#50 id=50 data-nosnippet>50</a> <span class="kw">type </span><span class="prelude-val">Err </span>= Error; |
| <a href=#51 id=51 data-nosnippet>51</a> <span class="kw">fn </span>from_str(s: <span class="kw-2">&</span>str) -> <span class="prelude-ty">Result</span><<span class="self">Self</span>> { |
| <a href=#52 id=52 data-nosnippet>52</a> <span class="kw">let </span>tokens = lexer::tokenize(s)<span class="question-mark">?</span>; |
| <a href=#53 id=53 data-nosnippet>53</a> parser::parse(tokens) |
| <a href=#54 id=54 data-nosnippet>54</a> } |
| <a href=#55 id=55 data-nosnippet>55</a>} |
| <a href=#56 id=56 data-nosnippet>56</a> |
| <a href=#57 id=57 data-nosnippet>57</a><span class="kw">impl </span>Grammar { |
| <a href=#58 id=58 data-nosnippet>58</a> <span class="doccomment">/// Returns an iterator over all nodes in the grammar. |
| <a href=#59 id=59 data-nosnippet>59</a> </span><span class="kw">pub fn </span>iter(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw">impl </span>Iterator<Item = Node> + <span class="lifetime">'_ </span>{ |
| <a href=#60 id=60 data-nosnippet>60</a> (<span class="number">0</span>..<span class="self">self</span>.nodes.len()).map(Node) |
| <a href=#61 id=61 data-nosnippet>61</a> } |
| <a href=#62 id=62 data-nosnippet>62</a> |
| <a href=#63 id=63 data-nosnippet>63</a> <span class="doccomment">/// Returns an iterator over all tokens in the grammar. |
| <a href=#64 id=64 data-nosnippet>64</a> </span><span class="kw">pub fn </span>tokens(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw">impl </span>Iterator<Item = Token> + <span class="lifetime">'_ </span>{ |
| <a href=#65 id=65 data-nosnippet>65</a> (<span class="number">0</span>..<span class="self">self</span>.tokens.len()).map(Token) |
| <a href=#66 id=66 data-nosnippet>66</a> } |
| <a href=#67 id=67 data-nosnippet>67</a>} |
| <a href=#68 id=68 data-nosnippet>68</a> |
| <a href=#69 id=69 data-nosnippet>69</a><span class="kw">impl </span>ops::Index<Node> <span class="kw">for </span>Grammar { |
| <a href=#70 id=70 data-nosnippet>70</a> <span class="kw">type </span>Output = NodeData; |
| <a href=#71 id=71 data-nosnippet>71</a> <span class="kw">fn </span>index(<span class="kw-2">&</span><span class="self">self</span>, Node(index): Node) -> <span class="kw-2">&</span>NodeData { |
| <a href=#72 id=72 data-nosnippet>72</a> <span class="kw-2">&</span><span class="self">self</span>.nodes[index] |
| <a href=#73 id=73 data-nosnippet>73</a> } |
| <a href=#74 id=74 data-nosnippet>74</a>} |
| <a href=#75 id=75 data-nosnippet>75</a> |
| <a href=#76 id=76 data-nosnippet>76</a><span class="kw">impl </span>ops::Index<Token> <span class="kw">for </span>Grammar { |
| <a href=#77 id=77 data-nosnippet>77</a> <span class="kw">type </span>Output = TokenData; |
| <a href=#78 id=78 data-nosnippet>78</a> <span class="kw">fn </span>index(<span class="kw-2">&</span><span class="self">self</span>, Token(index): Token) -> <span class="kw-2">&</span>TokenData { |
| <a href=#79 id=79 data-nosnippet>79</a> <span class="kw-2">&</span><span class="self">self</span>.tokens[index] |
| <a href=#80 id=80 data-nosnippet>80</a> } |
| <a href=#81 id=81 data-nosnippet>81</a>} |
| <a href=#82 id=82 data-nosnippet>82</a> |
| <a href=#83 id=83 data-nosnippet>83</a><span class="doccomment">/// Data about a node. |
| <a href=#84 id=84 data-nosnippet>84</a></span><span class="attr">#[derive(Debug)] |
| <a href=#85 id=85 data-nosnippet>85</a></span><span class="kw">pub struct </span>NodeData { |
| <a href=#86 id=86 data-nosnippet>86</a> <span class="doccomment">/// The name of the node. |
| <a href=#87 id=87 data-nosnippet>87</a> /// |
| <a href=#88 id=88 data-nosnippet>88</a> /// In the rule `A = 'b' | 'c'`, this is `"A"`. |
| <a href=#89 id=89 data-nosnippet>89</a> </span><span class="kw">pub </span>name: String, |
| <a href=#90 id=90 data-nosnippet>90</a> <span class="doccomment">/// The rule for this node. |
| <a href=#91 id=91 data-nosnippet>91</a> /// |
| <a href=#92 id=92 data-nosnippet>92</a> /// In the rule `A = 'b' | 'c'`, this represents `'b' | 'c'`. |
| <a href=#93 id=93 data-nosnippet>93</a> </span><span class="kw">pub </span>rule: Rule, |
| <a href=#94 id=94 data-nosnippet>94</a>} |
| <a href=#95 id=95 data-nosnippet>95</a> |
| <a href=#96 id=96 data-nosnippet>96</a><span class="doccomment">/// Data about a token. |
| <a href=#97 id=97 data-nosnippet>97</a></span><span class="attr">#[derive(Debug)] |
| <a href=#98 id=98 data-nosnippet>98</a></span><span class="kw">pub struct </span>TokenData { |
| <a href=#99 id=99 data-nosnippet>99</a> <span class="doccomment">/// The name of the token. |
| <a href=#100 id=100 data-nosnippet>100</a> </span><span class="kw">pub </span>name: String, |
| <a href=#101 id=101 data-nosnippet>101</a>} |
| <a href=#102 id=102 data-nosnippet>102</a> |
| <a href=#103 id=103 data-nosnippet>103</a><span class="doccomment">/// A production rule. |
| <a href=#104 id=104 data-nosnippet>104</a></span><span class="attr">#[derive(Debug, Clone, Eq, PartialEq)] |
| <a href=#105 id=105 data-nosnippet>105</a></span><span class="kw">pub enum </span>Rule { |
| <a href=#106 id=106 data-nosnippet>106</a> <span class="doccomment">/// A labeled rule, like `a:B` (`"a"` is the label, `B` is the rule). |
| <a href=#107 id=107 data-nosnippet>107</a> </span>Labeled { |
| <a href=#108 id=108 data-nosnippet>108</a> <span class="doccomment">/// The label. |
| <a href=#109 id=109 data-nosnippet>109</a> </span>label: String, |
| <a href=#110 id=110 data-nosnippet>110</a> <span class="doccomment">/// The rule. |
| <a href=#111 id=111 data-nosnippet>111</a> </span>rule: Box<Rule>, |
| <a href=#112 id=112 data-nosnippet>112</a> }, |
| <a href=#113 id=113 data-nosnippet>113</a> <span class="doccomment">/// A node, like `A`. |
| <a href=#114 id=114 data-nosnippet>114</a> </span>Node(Node), |
| <a href=#115 id=115 data-nosnippet>115</a> <span class="doccomment">/// A token, like `'struct'`. |
| <a href=#116 id=116 data-nosnippet>116</a> </span>Token(Token), |
| <a href=#117 id=117 data-nosnippet>117</a> <span class="doccomment">/// A sequence of rules, like `'while' '(' Expr ')' Stmt`. |
| <a href=#118 id=118 data-nosnippet>118</a> </span>Seq(Vec<Rule>), |
| <a href=#119 id=119 data-nosnippet>119</a> <span class="doccomment">/// An alternative between many rules, like `'+' | '-' | '*' | '/'`. |
| <a href=#120 id=120 data-nosnippet>120</a> </span>Alt(Vec<Rule>), |
| <a href=#121 id=121 data-nosnippet>121</a> <span class="doccomment">/// An optional rule, like `A?`. |
| <a href=#122 id=122 data-nosnippet>122</a> </span>Opt(Box<Rule>), |
| <a href=#123 id=123 data-nosnippet>123</a> <span class="doccomment">/// A repeated rule, like `A*`. |
| <a href=#124 id=124 data-nosnippet>124</a> </span>Rep(Box<Rule>), |
| <a href=#125 id=125 data-nosnippet>125</a>} |
| <a href=#126 id=126 data-nosnippet>126</a> |
| <a href=#127 id=127 data-nosnippet>127</a><span class="attr">#[test] |
| <a href=#128 id=128 data-nosnippet>128</a></span><span class="kw">fn </span>smoke() { |
| <a href=#129 id=129 data-nosnippet>129</a> <span class="kw">let </span>grammar = <span class="macro">include_str!</span>(<span class="string">"../ungrammar.ungram"</span>); |
| <a href=#130 id=130 data-nosnippet>130</a> <span class="kw">let </span>grammar = grammar.parse::<Grammar>().unwrap(); |
| <a href=#131 id=131 data-nosnippet>131</a> drop(grammar) |
| <a href=#132 id=132 data-nosnippet>132</a>} |
| <a href=#133 id=133 data-nosnippet>133</a> |
| <a href=#134 id=134 data-nosnippet>134</a><span class="attr">#[test] |
| <a href=#135 id=135 data-nosnippet>135</a></span><span class="kw">fn </span>test_rust_grammar() { |
| <a href=#136 id=136 data-nosnippet>136</a> <span class="kw">let _ </span>= rust_grammar(); |
| <a href=#137 id=137 data-nosnippet>137</a>}</code></pre></div></section></main></body></html> |
